Basement Waterproofing Design; High claims bring change

1st March 2014

Swimming pool stays dry due to good waterproofing design


Basement Waterproofing design; high claims bring change.

There’s a refreshing wind of change blowing through the basement waterproofing industry. Most people wouldn’t even be aware of it, but for those working on and designing buildings with basements, this is a paradigm shift in the way basement waterproofing is approached.





CSSW Basement waterproofing designer to BS8102

























It doesn’t involve new materials or different application methods – these are already well established and defined in BS 8102: “Code of practice for the protection of below ground structures against water from the ground” 2009.

So what’s changed in Basement waterproofing design?

Well, it’s more a case of who does the work, rather than how. This is because the principle insurance body’s, which underwrite the performance of basement waterproofing systems in new buildings, have taken some truly groundbreaking decisions.

After years of paying many millions of pounds in claims, brought about by failed basement waterproofing design systems, they have investigated the reasons behind these problems and taken action to improve standards and reduce their financial risk. Often the failures are due to poor basement waterproofing design. In these cases the failure chances of a failure, were a lottery; if the basement was never subject to a head of groundwater, things were fine. However, where ground water comes to bear – even temporarily, floods and seepage occurs.

example of failed basement waterproofing

























Even in cases where installation was applied diligently, disaster happened. BS8102 places responsibilities firmly with the basement-waterproofing designer; workmanship defects have to be considered and the design has to take this into account. Thus if a workmanship defect causes a leak, the basement waterproofing designer can be help responsible, for not ensuring that the system could be repaired, maintained or had sufficient redundancy built-in, to avoid the problem.

Flooded or even gently seeping basements cost a fortune to repair. Often the repair is a complete strip out, with huge associated and consequential costs. Research has shown that getting a basement waterproofing design correct, before construction is crucial. Ensuring that trained and experienced specialist contractors install the system reduces claims by a huge margin and, ensuring that the guidance of BS102 is followed as far as reasonably practical, saves money. We are talking tens of millions of pounds saved each year.

BS8102 has been around for year, however after it was revised in 2009, take up of some of the new revisions was slow. Now that is changed and architects, builders and developers are seeking to ensure compliance.

It is the insurance industry, which has finally brought about the change. Lenders and buyers demand ten-year insurance on new buildings. Without it, any building is a potential dead-loss, as buyers cannot raise finance to buy, they lose confidence and in many cases lenders will not even invest in the construction, if insurance for the designed scheme is not approved in advance.

So what are the insurers demanding in respect of basement waterproofing schemes?

The first demand is that any basement waterproofing design should include input from a specialist basement-waterproofing designer.

The second demand is that the installation of the basement waterproofing system should be carried out by a trained and experienced specialist, who should issue an insurance for the full ten year period.

In practice this means that for most new build basement schemes, insurance companies want to see involvement of a qualified basement waterproofing designer, at an early stage.

A basement waterproofed by Deepshield and now a swimming pool

























One way of doing this is to employ a CSSW qualified surveyor to work with the design team. CSSW is ‘Certificated Surveyor In Structural Waterproofing’ and has been around for over ten years. The vast majority of current CSSW qualified surveyor’s work for or own specialist basement waterproofing companies. Most of these company’s are in the ‘quality’ end of the basement waterproofing industry, as in general the less skilled and committed ‘specialists’ don’t bother with expensive training and examination.

There are also many very highly qualified engineers and geotechnical professionals with these skills, lots of whom would not bother with CSSW as they already have the experience and knowledge required to do this work. CSSW is a narrower qualification, based on examination of candidate’s knowledge of waterproofing systems and guidance in BS8102. The examination also demands that CSSW holders can design a correct waterproofing method, given a range of site conditions. Aural examinations are incorporated too, to dig a little deeper into CSSW candidates core knowledge.

In addition, the second insurance insistence is the application approach – a qualified basement waterproofing contractor is essential now. For practical purposes this means that contractors should have CSSW qualified surveyors and be members of the Property Care Association. PCA membership allows suitably qualified members to specify basement-waterproofing systems and to insure the installed system through The Guarantee Protection Trust for ten years.

At last the decline in quality of basement waterproofing is addressed, by this belt-and-braces approach.

1. Good design with CSSW involvement or equivalent
2. High quality installation by Property Care Association members…. and
3. A ten year insurance policy on the performance of the entire basement waterproofing system.

Deepshield basement waterproofing success



























Time will tell, but the future looks much brighter for the insurers, now that basement waterproofing is get the attention and care that such crucial work involves.

Of course this is good news for CSSW holders and PCA members like myself. However, it’s even better news for those who own, build and insure structures below ground.

Filed under: Materials, Waterproofing,

Tagged as: basement waterproofing, structural waterproofing, BS8102, CSSW,

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